1. Field of the Invention
This invention relates to a surgical cutter for use in laparoscopic surgery. In particular, the invention relates to a device for enlarging the incision made during laparoscopic surgery to allow for the removal of items larger than the incision, such as a gall bladder.
2. The Prior Art
Laparoscopic cholecystectomy, or gall bladder removal, is initiated by making a 10-12 mm incision just beneath the umbilicus. A video camera is then placed through this incision during the surgery. Upon completion of the operation, the gall bladder is removed through this 10-12 mm incision. When the gall bladder is very large or is swollen from inflammation, it cannot be removed from this incision and becomes lodged. This requires the placement of retractors for exposure, a clamp beneath the fascia and an incision over the clamp with a scalpel to enlarge the fascia. However, use of an ordinary surgeon's knife or scalpel to enlarge an endoscopic incision is not acceptable because of the hazard of making an incision of uncontrolled length and of the hazard of damaging the gall bladder.
A second technique used for an entrapped gall bladder is to open the gall bladder at the top portion protruding from the incision and empty the gall bladder until its contents are reduced to the point where the gall bladder is small enough to be withdrawn from the incision. However, this technique is undesirable because the gall bladder contents, including stones and bile, are at times spilled on the abdominal wall of the patient.
One type of device used to enlarge the incision to allow for passage of the entire gall bladder is shown in U.S. Pat. No. 5,667,519 to Ramsey. This device comprises a handle having a blade resting on a guide with a semicircular cross section. The guide fits along the cannula and guides the blade downward in a controlled manner.